Poster Abstracts

Name/Affiliation:  Sebastien Lepine (Georgia State University)

Title:  Revised spectroscopic distances and kinematics of local field M dwarfs and M subdwarfs.

We combine parallax measurements from the literature to optical spectroscopy of 1459 M dwarfs and M subdwarfs to update the calibration of the spectroscopic distance relationships, and in particular their dependence on metallicity subclass (dM, sdM, esdM, usdM). We use the revised calibration to calculate distances and transverse motions for 4525 spectroscopically confirmed M dwarfs, 183 subdwarfs (sdM), 134 extreme subdwarfs (esdM) and 105 ultrasubdwarfs (usdM) in the solar vicinity (d<200pc). Results demonstrate again the clear association of esdM and usdM stars with the Galactic halo population. The velocity-space distribution shows substructure in the local disk population consistent with previous studies, including the Coma, Sirius, and Hercules streams. However, we find no evidence for dynamical substructure in the local thick disk and halo populations.